It would appear so. I called Focus on the Family and spoke with Steve, a representative for Dr. Dobson. Steve said they were completely unaware of any comment by C. Everett Koop calling Dr. Dobson homophobic. That's not to say it's false, but they are unaware of any comment.
I tried to find the Koop quote before posting the article and couldn't. It's Koop still around? I'd like to ask him myself, and there's another Koop quote regarding Dr. Paul Cameron that I'd like to ask about...
I believe dr. Koop is still around; although he did have that .com bust a few years back. But I am pretty sure I haven't read an obit. That said I wouldn't have a clue as to how to go about finding him.
Koop once went over to L'abri to study with Francis Schaeffer. Never in a million years would he call Dobson anything but a hero, that is unless he's done a true about face. But that would be so highly publicized that we would all have known about it.